This application relates to a novel process for the preparation of certain N-carbamoyl ethyl oxanilates. The compounds prepared by the process have the formula ##STR4## in which X and Y are independently selected from the group consisting of chloro, bromo and trifluoromethyl; n is either zero or one; and R and R.sub.1 are independently selected from the group consisting of lower alkyl and lower alkoxy from C.sub.1 to C.sub.3 inclusive, or R and R.sub.1 taken together is selected from the group consisting of ##STR5##
Compounds of this type, possessing utility as post and/or pre-emergence herbicides, are disclosed in the co-pending application of Edmund J. Gaughan and George B. Large titled "N-Carbamoyl Ethyl Oxanilates," Ser. No. 559,104, filed Mar. 17, 1975, now abandoned. It is disclosed therein that the compounds are prepared by reacting a 1,3,3-trisubstituted urea with sodium hydride to form a sodium salt of the urea, followed by reacting the sodium salt with ethyl oxalyl chloride to obtain the desired compound. The reactions shown in the application were all carried out using tetrahydrofuran as a solvent, and the reaction mixture was maintained under an argon blanket during at least part of the process.
It is an object of the present invention to provide a process for the preparation of N-carbamoyl ethyl oxanilates in a single step.
A further object of this invention is to provide a process for the preparation of N-carbamoyl ethyl oxanilates which can be conducted using a solvent less costly than tetrahydrofuran.
A further object of the present invention is to provide a process for the preparation of N-carbamoyl ethyl oxanilates which does not require the use of sodium hydride.
Yet another object of the present invention is to provide a process for the preparation of N-carbamoyl ethyl oxanilates which does not require maintenance of an inert atmosphere during conduct of the process.
A still further object of the present invention is to provide an improved process for the production of N-carbamoyl ethyl oxanilates of good purity and in high yield.